Re: 1974 Evinrude 9.9 won’t idle at low RPMs, need help

[frankr]

quote Hotpickle:

quote FrankR:

My 1st guess is that the high speed orifice (jet) is partially clogged. That would account for the excessive choking need. 2nd guess (well actually 1st) is have you heard yet that those motors were notorious for fouling spark plugs? Are you sure it is running on both cylinders? Try new plugs, I don’t care if they were just put in recently. I’ve seen brand new motors that wouldn’t run one weekend without fouling plugs. Bad.

3rd guess is major air leak. But let’s not go there yet.

The high speed jet is clean, i didnt have to get anything out of there. I snaked through with a wire and checked it.

I did have black sooty residue on the spark plugs, one had more than the other. I have read thats a sign of a heat range that is too cold?

Possibly too cold, more likely just the old fouling problem rearing it’s ugly head. But we can’t automatically jump to conclusions, it could be too rich (other one lean) etc. Hotter plugs may help burn the crud off. Try ’em.